French President Nicolas Sarkozy assumed office with a promise to turn France firmly back toward the Atlantic, a cowboy persona and a not-so-affectionate nickname: “Sarko the American.” Barack Obama, meanwhile, is regularly dinged by critics for not embracing his inner cowboy enough and for having a preference for multi-lateralism that sounds, to Republicans, well ... a little too European for comfort.

Now Sarkozy stands at the fore of a coalition of the willing battling Col. Muammar Qadhafi in Libya, where French planes fired the first shots Saturday. And while the U.S. is providing military heft, Obama has gladly surrendered the limelight and, perhaps, a measure of control to a French leader with very different ambitions and interests.

“France has decided to assume its role, its role before history,” Sarkozy announced, as his country’s warplanes opened the attack on Qadhafi’s forces.

And from that moment on, in a very real way, Obama was betting the success of this unexpected and controversial North African intervention on the constancy and competence of a French colleague who could hardly be more different than the deliberate and cautious former senator from Illinois.

Sarkozy’s stamp on the conflict has been unmistakable. Cable news in the U.S. on Monday featured the celebrity philosopher Bernard-Henri Levy, an unexpected Sarkozy ally, barking praise for the French president at a CNN anchor and elated Libyan opposition fighters shouting, “Merci, Sarkozy.”

And Sarkozy was indeed a central force in goading the world to act. “Sarkozy has a huge investment in seeing Qadhafi go,” said Justin Vaisse, the director of research for the Center on the United States and Europe at Brookings in Washington. “He’s going to be a constant force in favor of hardening the stance and the action.”

But while Sarkozy’s zeal may have been helpful in rousing an international coalition to intervene, that passion could cause headaches in Washington. The American efforts to limit and clearly define the effort to stop Qadhafi in his tracks and — leaders hope — end his rule may well depend on the decisions of the impulsive Sarkozy, for whom Libya is both a crisis in his backyard and, analysts say, a political opportunity.

One central difference between Paris and Washington is the issue of geography. Libya may be a strategic interest for the United States, but a crisis there presents a more immediate challenge to France and other European countries, which buy Libyan oil and gas and fear yet another wave of North African refugees.

“What Sarkozy saw was that Qadhafi has leverage that could make him horribly troublesome for everyone — energy, inmmigration, terrorism,” Vaise said. “And these would be directed at the Europeans, not the Americans.”

But Sarkozy also has an opportunity to recapture some of the international glory that has marked the high points of his presidency and restored France’s sense of its ability to punch above its weight, as when he negotiated a 2008 ceasefire between Russia and Georgia. That image of international command, central to the narrative of his rise to power, had suffered badly this year when he was forced to fire his foreign minister for her close ties to a Tunisian dictator whose fall Sarkozy’s government largely overlooked.

The aggressive French reaction to Libya was “partly because he took a lot of heat for being behind the curve on Tunisia, and partly because Sarkozy is not one who sits still,” said Charles Kupchan, a former director for European affairs at the National Security Council who is now an analyst for the Council on Foreign Relations.

Sarkozy took a diplomatic risk on Libya amid a personal political crisis: his approval ratings are the lowest of any president in modern French history, dropping to 31 percent in a survey conducted for Le Point magazine this month. His center-right party was badly beaten in local elections this week, picking up just 17 percent of seats around the country, and his own reelection looms in May 2012.

“Libya was for him a very good case where he could reverse the situation and show that he’s a man of determination and leadership,” said Pierre Haski, a co-founder of the French news site Rue89.

Sarkozy’s action has drawn welcome comparisons with his predecessors.

Levy compared Sarkozy’s move to President Jacques Chirac’s 1995 order to French troops to retake a bridge in Bosnia, an act that helped stiffen the overall Western response to the Balkan bloodshed.

Sarkozy has also drawn a parallel with President Francois Mitterand’s participation in the broad coalition against Saddam Hussein in the 1991 Gulf War, a comparison the sympathetic Journal de Dimanche suggested was particularly welcome because, in this case, he’s the one playing the lead role.

“It is something to see the French flags in Benghazi,” he told the paper.

Sarkozy’s aggressive posture has, so far, suited U.S. interests. Obama has sought to avoid putting an American stamp on a third war in a Muslim country, and Sarkozy has obliged. He’s also followed a traditional Gaullist impulse to conduct the operation through an ad hoc alliance rather than NATO, ruffling some European feathers but satisfying the American desire to keep a low profile.

France has cast that decision as a bow to the desires of the Arab League.

“The Arab League does not wish the operation to be entirely placed under NATO responsibility. It isn’t NATO which has taken the initiative up to now,” French Foreign Minister Alain Juppe told reporters at a European Union meeting in Brussels.

But analysts said that if the fight drags on, differences between the American and French goals could emerge.

“It’s the whole question of coordination of future efforts — once you’ve eliminated the air defense sites — then what next?” said Stephen Flanagan, the Henry Kissinger chair at the Center for Strategic and International Studies in Washington. “That’s where this could become complicated — especially if its not run as a NATO.”

And Sarkozy, as leery as the Americans of a drawn-out conflict, may be more willing to ramp up the engagment — a development that would likely enrage already skeptical members of Congress, many of whom do not have particularly warm memories of French leadership in past crises.

“France doesn’t have two wars on its hands like Obama,” said Rue 89’s Haski. “I’m sure Sarkozy is ready to go for an escalation if needed, and there you could have very heated arguments between the French and Americans.”

— Byron Tau contributed to this story.
CORRECTION: An earlier version of this story misidentified the French news site Rue89 and inaccurately attributed a quotation from Rue 89’s Pierre Haski.